DSH Pin-Sessions: Pin Sidebar Sessions for Quick Access

`fallow5/dsh-pin-sessions` is a DeepSeek Harness (DSH) plugin designed to address navigation difficulties caused by an overly long session list in the sidebar. It allows users to pin active sessions to the top of the sidebar and hide them from the workspace, while centrally managing hidden sessions through an archive panel that supports bulk operations, pagination, and grouping by workspace. The plugin depends on `dsh-session-context-menu` to extend the right-click context menu, adopts a standard host-client separation architecture, and optimizes the user experience for frequently switching between multiple workflows.